Winter 2015 Prosopagnosia Research Center Face to Face Prosopagnosia Research & Community This newsletter is getting out a bit later than we would have liked, because we’ve been so busy shoveling snow this winter! We hope you will contact us if you have thoughts or feedback to share! -Prosopagnosia Research Center ([email protected]) Face Selective Brain Areas and Prosopagnosia by Brad Duchaine The Classics In this section, we summarize a classic paper in face In the 1990s, cognitive neuroscientists began using recognition research. If you would like access to the functional magnetic resonance imaging (fMRI) to measure original article please visit https://www.cnbc.cmu.edu/~behrmann/dlpapers/Mo which brain areas became active during particular scovitch_et_al_1997 psychological tasks. Several research groups were interested in seeing which areas became active when Moscovitch, M., Winocur, G. and Behrmann, people viewed faces, partially because reports of M. (1997). What is special about face recognition? Nineteen experiments on a prosopagnosia suggested face processing may depend on person with visual object agnosia and specialized brain mechanisms. dyslexia but normal face recognition. Journal of Cognitive Neuroscience, 9, 5, 555-604. In 1997, papers from a group at Harvard (Kanwisher et al. 1997) and another group at Yale (McCarthy et al. 1997) Some people with prosopagnosia can reported that a region in the fusiform gyrus responded recognize other objects normally despite much more strongly to faces than to other objects (See severe face problems with faces. This figure below). The fusiform gyrus is a brain region in the condition is called 'pure prosopagnosia', occipital and temporal lobe. The activation in the fusiform because faces appear to be the only gyrus seen in response to faces fit nicely with evidence that category these individuals have problems brain damage to this part of the brain led to prosopagnosia with. Pure prosopagnosia suggests face and thus was critical for face processing. This activation is processing depends on different processes often called the 'fusiform face area' (FFA), and it is one of than other types of visual recognition. If the most well known findings from fMRI research. face recognition depends on specialized mechanisms, you might expect the In the nearly twenty years since the FFA was discovered, opposite condition might also exist. Just researchers have identified a number of other face- such a case was reported in a classic paper selective areas in the occipital, temporal, and frontal lobes from 1997. (See Figure). Shortly after the FFA was reported, the occipital face area (OFA) was found more toward the back Morris Moscovitch is a prominent of the brain, and a region in the posterior superior neuropsychologist at the University of temporal sulcus was found in a region on the side of the Toronto, and he published an influential temporal lobe. More recently, additional areas have been series of papers about a man named Mr found in the anterior temporal lobe, the anterior superior CK who suffered brain damage after he temporal sulcus, and the inferior frontal gyrus. These areas was hit by a car while jogging. As a result are typically present in both the left and right hemispheres, of the brain damage, CK suffers from but the response in the right hemisphere is usually severely impaired object recognition and stronger. word recognition. (continued on Pg. 2) (continued on Pg. 4) Face to Face, Prosopagnosia Research Center Winter, 2015 Face Selective Brain Areas…, continued from pg 1. The existence of these areas has led to many proposals and experiments about the function of these areas, but our understanding of the function of these areas still remains sketchy. Not surprisingly, research into the neural basis of prosopagnosia has focused on these face-selective regions. In studies of people with developmental prosopagnosia, early fMRI work with small numbers of participants showed that these areas were usually present despite severe face recognition impairments. This finding came as a surprise to some researchers, but more recent studies with larger samples of subjects suggests that face-selective areas in people with developmental prosopagnosia are smaller and less responsive to faces than these areas in people without prosopagnosia. In some cases, people with developmental prosopagnosia don't show any regions that show a stronger response to faces than to objects. Much more work however will be necessary to better understand the neural abnormalities in developmental prosopagnosia. One intriguing question is whether abnormalities in different face-selective areas lead to different types of developmental prosopagnosia, and this is a question that is currently being investigated by the prosopagnosia lab at Dartmouth. Another approach to the question of the function of face- selective areas is to study what happens when face-selective areas are lost due to brain damage. Over the last few years, the lab at Dartmouth has carried out fMRI and extensive behavioral testing with a group of people with acquired Face-selective areas. The six face-selective areas prosopagnosia, and they plan to test more people in the discussed here are shown in two views of the brain coming years. In a recently published paper from the of a participant with normal face processing. The view at the top of the figure shows the right Dartmouth lab (Yang et al., in press), they demonstrated that hemisphere ventral face-selective areas: occipital a man referred to as Galen (pseudonyms are usually used in face area (OFA), fusiform face area (FFA), and these sorts of studies) lost the FFA and OFA in his right ATL-FA. The view below shows the dorsal face- hemisphere following brain surgery. Despite the loss of these selective areas: pSTS-FA, aSTS-FA, and IFG-FA. regions, his other face-selective regions appear to respond normally to faces. Most surprising to us was the normal response of the face-selective area in the right anterior temporal lobe, because this area would be expected to receive its primary input from the FFA and OFA. Studies like this one shed light on how the face areas interact with one another and demonstrate the value of studying face areas in prosopagnosia. ∇ Kanwisher, N., McDermott, J., & Chun, M. (1997) The Fusiform Face Area: A Module in Human Extrastriate Cortex Specialized for the Perception of Faces. Journal of Neuroscience. 17: 4302-4311. McCarthy, G., Puce, A., Gore, J.C., & Allison, T. (1997) Face-Specific Processing in the Human Fusiform Gyrus, Journal of Cognitive Neuroscience, 9: 605-610. Yang, H., Susilo, T., & Duchaine, B. (in press). The anterior temporal face area contains invariant representations of identity that can persist despite the loss of right FFA and OFA. Cerebral Cortex. Face to Face, Prosopagnosia Research Center Winter, 2015 Scaling Up Prosopagnosia Research by Tirta Susilo In the last decade or so we have learned a lot about developmental prosopagnosia from studying some of you in our laboratories. Along the way we have discovered important things about prosopagnosia and how normal face recognition is supposed to work, some of which we've shared in the newsletter. But most of these studies have very small samples. Prosopagnosia studies with samples above 10 are rare, and the biggest study to date has about 40 participants. For comparison, studies of dyslexia regularly test hundreds of people, and the biggest study of synesthesia has a sample of 19,133. There is a clear drawback of studies with small samples: they are not suitable for drawing precise estimates that would help us better characterize prosopagnosia. For examples, we don’t have good answers to fundamental questions like: What is the proportion of people with prosopagnosia who also have difficulties recognizing facial expressions? How common are people whose visual recognition problems are strictly restricted to faces and nothing else (called pure prosopagnosia)? Do the majority of prosopagnosics have problems processing a face as a single unit of visual analysis (a phenomenon known as holistic face perception)? We need to answer these questions and many others if we are to have a deep understanding of prosopagnosia and how face recognition can be improved in prosopagnosia. Thanks to the possibility of online testing, we now have the means to address these issue with large samples. Over the last few years we have designed and refined a wide range of tests that can be administered online. We, and others, have shown that these tests produce data similar to those collected in the laboratory. We are really excited about online tests because they allow us to scale up our research significantly without sacrificing quality, and more of you will be able to participate in our studies and learn about yourself without having to leave home. More than 10,000 people have registered at www.faceblind.org because they have face recognition problems. This means we have the potential to run prosopagnosia studies with hundreds or even in thousands of participants. For prosopagnosia research, these numbers are unprecedented. If many of you participate in our online studies, we will be in a great position to answer the basic questions above and many more. So please keep your eyes peeled for an email inviting you to participate in our studies. Together we'll take prosopagnosia research to new heights! ∇ Prosopagnosia in the News! Developmental prosopagnosia in a man tested in the Birkbeck lab: http://www.huffingtonpost.co.uk/2015/01/20/prosopagnosia-face-blindness-recognise-own- family_n_6501638.html Acquired prosopagnosia in a man tested in several London labs: http://www.dailymail.co.uk/news/article-2995696/Father-left-unable-recognise-family-s-faces-suffering- stroke-realised-problem-struggled-son-school-gates White matter deficits in developmental prosopagnosia (Stanford): http://news.stanford.edu/news/2015/january/face-blind-brain-013015.html Face to Face, Prosopagnosia Research Center Winter, 2015 The Classics, continued from pg 1.